The list of House Freedom Caucus members being targeted by President Trump for sinking Republicans’ ObamaCare overhaul plan grew Saturday when the White House singled out Michigan GOP Rep. Justin Amash for a primary defeat.

“Donald Trump is bringing auto plants & jobs back to Michigan,” tweeted White House social media Director Dan Scavino Jr. “@justinamash is a big liability. #TrumpTrain, defeat him in primary.”

Most of the ultra-conservative caucus’ roughly 35 members withheld their support for the Republican House leadership’s overhaul plan, which kept it from even getting a final vote in the GOP-led chamber, despite Trump’s rigorous dealmaking efforts.

The president invited caucus leaders to the White House and met with them and others in the House Republican conference on Capitol Hill in the days before the scheduled final vote.

Trump and House Speaker Paul Ryan, R-Wis., purportedly agreed to cancel the vote, instead of forcing non-supporters to cast “no” ballots on the record. However, Trump still appears bent on political revenge, with the White House suggesting support for a more moderate conservative against Amash in next year’s midterm elections.

“The Freedom Caucus will hurt the entire Republican agenda if they don't get on the team, & fast,” Trump tweeted Thursday. “We must fight them, & Dems, in 2018!”

Also that day, The Post and Courier newspaper in South Carolina reported that Trump dared Freedom Caucus member Rep. Mark Sanford, R-S.C., to vote against the overhaul bill.

Sanford, who with Kentucky GOP Sen. Rand Paul has a competing ObamaCare replacement bill, said White House Budget Director Mick Mulvaney told him: "The president asked me to look you square in the eyes and to say that he hoped that you voted ‘no’ on this bill so he could run (a primary challenger) against you in 2018," according to the paper.

The Freedom Caucus members who opposed the House leadership plan say it doesn’t go far enough to repeal and replace ObamaCare, and they largely appear entrenched in that position.

Amash and Stanford are not the first Freedom Caucus members on Trump’s political hit list. Trump told caucus Chairman Mark Meadows, R-N.C., at the closed-door Capitol Hill meeting: “Oh Mark, I'm coming after you.”

Daniel Jacobson, a former Obama White House lawyer, argued Saturday that Scavino's tweet violates federal law about mixing official business with politics.

"This violates the Hatch Act. WH staff can't use an official or de facto govt Twitter acct (which this is) to call for defeat of a candidate," he tweeted.